1. Field of the Invention
This invention relates to a combined lawn mowing and lawn trimming machine of the type that is mounted on a frame and supported on two wheels.
2. Description of the Prior Art
The trend in lawn maintenance has always been to use a lawn mower to cut the lawn and a lawn trimmer to trim the edges of the lawn, including areas of vegetation that boarder fences and buildings. Recently, hand held line trimmers have become popular for performing the trimming operations. But, except for the small lawn, hand held trimmers are impractical for some people to use since they are too heavy to carry around for extended periods of time. Even with use on a small lawn, the difficulty of controlling hand held trimmers is experienced. The lack of control problem results in unevenly cut vegetation and scalping of the ground at the roots of the vegetation. Also, the lack of control problem is often compounded by user fatigue associated with carrying around the hand held trimmer.
Quite recently, a trend has developed toward making the hand held trimmer more suitable to the user and more compatible with the user's needs. Such efforts have included designing wheeled carriages and dollies to be used with the trimmers. But, while these devices have done much to alleviate user fatigue, they have done little to aid the user in controlling and positioning the rotating cutting head. For example, H. J. Enbusk in U.S. Pat. No. 4,442,659 discloses a dolly for a line trimmer that must be held in one hand while the trimmer, which is pivotally mounted to the dolly, is held in the other hand. With this device, each hand performs a separate positioning function resulting in an awkward combination for controlling the cutting head. Also, these types of devices do not confront the problem of having to use two separate machines for maintaining the lawn.
Prior art devices that combine mowing and trimming features in one machine are known. Such an apparatus is disclosed by Watrous in U.S. Pat. No. 2,669,826, wherein a two wheel lawn mower is disclosed having a forwardly mounted cutting head that is supported on a ground engaging shoe. In Watrous the axle and housing are pivotally connected, thereby permitting the entire cutting head to swing from side to side with respect to the rear wheels and handle. The plane of cutting remains parallel to the ground in each position of the cutting head. This limits the versatility of the machine, since the angle of the cutting plane cannot be changed.
In U.S. Pat. No. 4,077,191 to Pittinger, a filament-trimmer/mower is disclosed that includes a four wheel supported frame. Each of the front and rear wheel-and-axle assemblies are pivotally mounted with respect to the frame. Pittinger, however, suffers from the disadvantage that the rotating head is held in a fixed position between the wheels. Therefore, it is difficult to trim the vegetation growing along side a building or other structure, since the filament line would not normally extend outside the path of travel of the wheels.